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Spreading Speed of Magnetopause Reconnection X‐Lines Using Ground‐Satellite Coordination
Author(s) -
Zou Ying,
Walsh Brian M.,
Nishimura Yukitoshi,
Angelopoulos Vassilis,
Ruohoniemi J. Michael,
McWilliams Kathryn A.,
Nishitani Nozomu
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075765
Subject(s) - magnetopause , geophysics , physics , magnetic reconnection , field line , spacecraft , field (mathematics) , radar , magnetic field , computational physics , magnetosphere , aerospace engineering , astronomy , mathematics , quantum mechanics , pure mathematics , engineering
Conceptual and numerical models predict that magnetic reconnection starts at a localized region and then spreads out of the reconnection plane. At the Earth's magnetopause this spreading would occur primarily in local time along the boundary. Different simulations have found the spreading to occur at different speeds such as the Alfvén speed and speed of the current carriers. We use conjugate Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft and Super Dual Auroral Radar Network (SuperDARN) radar measurements to observationally determine the X‐line spreading speed at the magnetopause. THEMIS probes the reconnection parameters locally, and SuperDARN tracks the reconnection development remotely. Spreading speeds under different magnetopause boundary conditions are obtained and compared with model predictions. We find that while spreading under weak guide field could be explained by either the current carriers or the Alfvén waves, spreading under strong guide field is consistent only with the current carriers.